We report in-situ simultaneous monitoring of molecular vibrations of two components in organic photovoltaic blends using resonant Raman spectroscopy. Blend films were composed of a low bandgap copolymer thieno[3,2-b]thiophene-diketopyrrolopyrrole (DPPTTT) and (6,6)-phenyl-C71-butyric acid ester (PC70BM). Changes in Raman spectra associated with crystallization processes of each component and their impact on thin film morphology were studied during thermal annealing and cooling processes. Transition temperatures to crystalline phases in blends were measured at ∼150 °C and ∼170 °C for DPPTTT and PC70BM, respectively. Such phase changes lead to modifications in local chemical composition reducing relative Raman peak intensities (IPC70BM/IDPPTTT) from ∼0.4 in PC70BM-rich domains to ∼0.15 in homogeneous areas.
REFERENCES
1.
G.
Li
, R.
Zhu
, and Y.
Yang
, Nature Photon.
6
, 153
(2012
).2.
S.
Gunes
, H.
Neugebauer
, and N. S.
Sariciftci
, Chem. Rev.
107
, 1324
(2007
).3.
Z.
He
, C. M.
Zhong
, S. J.
Su
, M.
Xu
, H. B.
Wu
, and Y.
Cao
, Nature Photon.
6
, 591
(2012
).4.
C. E.
Small
, S.
Chen
, J.
Subbiah
, C. M.
Amb
, S. W.
Tsang
, T. H.
Lai
, J. R.
Reynolds
, and F.
So
, Nature Photon.
6
, 115
(2012
).5.
L. T.
Dou
, J. B.
You
, J.
Yang
, C. C.
Chen
, Y. J.
He
, S.
Murase
, T.
Moriarty
, K.
Emery
, G.
Li
, and Y.
Yang
, Nature Photon.
6
, 180
(2012
).6.
C. J.
Brabec
, M.
Heeney
, I.
McCulloch
, and J.
Nelson
, Chem. Soc. Rev.
40
, 1185
(2011
).7.
M. A.
Ruderer
and P.
Muller-Buschbaum
, Soft Matter
7
, 5482
(2011
).8.
W. C.
Tsoi
, D. T.
James
, J. S.
Kim
, P. G.
Nicholson
, C. E.
Murphy
, D. D. C.
Bradley
, J.
Nelson
, and J.-S.
Kim
, J. Am. Chem. Soc.
133
, 9834
(2011
).9.
X.
Wang
, D.
Zhang
, K.
Braun
, H. J.
Egelhaaf
, C. J.
Brabec
, and A. J.
Meixner
, Adv. Funct. Mater.
20
, 492
(2010
).10.
Y. Q.
Gao
, T. P.
Martin
, A. K.
Thomas
, and J. K.
Grey
, J. Phys. Chem. Lett.
1
, 178
(2010
).11.
E.
Klimov
, W.
Li
, X.
Yang
, G. G.
Hoffmann
, and J.
Loos
, Macromolecules
39
, 4493
(2006
).12.
Y. Q.
Gao
and J. K.
Grey
, J. Am. Chem. Soc.
131
, 9654
(2009
).13.
W. C.
Tsoi
, D. T.
James
, E. B.
Domingo
, J. S.
Kim
, M.
Al-Hashimi
, C. E.
Murphy
, N.
Stingelin
, M.
Heeney
, and J.-S.
Kim
, ACS Nano
6
, 9646
(2012
).14.
D. T.
James
, B. K. C.
Kjellander
, W. T. T.
Smaal
, G. H.
Gelinck
, C.
Combe
, I.
McCulloch
, R.
Wilson
, J. H.
Burroughes
, D. D. C.
Bradley
, and J.-S.
Kim
, ACS Nano
5
, 9824
(2011
).15.
J. M.
Winfield
, C. L.
Donley
, R. H.
Friend
, and J.-S.
Kim
, J. Appl. Phys.
107
, 024902
(2010
).16.
S.
Miller
, G.
Fanchini
, Y. Y.
Lin
, C.
Li
, C. W.
Chen
, W. F.
Su
, and M.
Chhowalla
, J. Mater. Chem.
18
, 306
(2008
).17.
J. S.
Kim
, P. K. H.
Ho
, C. E.
Murphy
, A. J. A. B.
Seeley
, I.
Grizzi
, J. H.
Burroughes
, and R. H.
Richard
, Chem. Phys. Lett.
386
, 2
(2004
).18.
H.
Liem
, P.
Etchegoin
, K. S.
Whitehead
, and D. D. C.
Bradley
, J. Appl. Phys.
92
, 1154
(2002
).19.
J. S.
Kim
, P. K. H.
Ho
, C. E.
Murphy
, N.
Baynes
, and R. H.
Friend
, Adv. Mater.
14
, 206
(2002
).20.
J. R.
Ferraro
and K.
Nakamoto
, Introductory Raman Spectroscopy
(Academic Press
, San Diego, CA
, 1994
).21.
Y.
Yacoby
and E.
Ehrenfreund
, in Light Scattering in Solids VI
, edited by M.
Cardona
and G.
Gfintherodt
(Springer
, Berlin/Heidelberg
, 1991
), Vol. 68
, p.73
.22.
Y. Y.
Liang
, Z.
Xu
, J. B.
Xia
, S. T.
Tsai
, Y.
Wu
, G.
Li
, C.
Ray
, and L.
Yu
, Adv. Mater.
22
, E135
(2010
).23.
H.
Bronstein
, Z. Y.
Chen
, R. S.
Ashraf
, W. M.
Zhang
, J. P.
Du
, J. R.
Durrant
, P. S.
Tuladhar
, K.
Song
, S. E.
Watkins
, Y.
Geerts
, M. M.
Wienk
, R. A. J.
Janssen
, T.
Anthopoulos
, H.
Sirringhaus
, M.
Heeney
, and I.
McCulloch
, J. Am. Chem. Soc.
133
, 3272
(2011
).24.
M. J.
Frisch
, G. W.
Trucks
, H. B.
Schlegel
, G. E.
Scuseria
, M. A.
Robb
, J. R.
Cheeseman
, G.
Scalmani
, V.
Barone
, B.
Mennucci
, G. A.
Petersson
et al. Gaussian 09, revision A.02 (Gaussian, Inc., Wallingford, CT, 2009
).25.
N. B.
Colthup
, L. H.
Daly
, and S. E.
Wiberley
, Introduction to Infrared and Raman Spectroscopy
, 3rd ed. (Academic Press
, Boston
, 1990
), p. 287
.26.
M.
Sims
, K.
Zheng
, M.
Campoy-Quiles
, R.
Xia
, P. N.
Stavrinou
, D. D. C.
Bradley
, and P.
Etchegoin
, J. Phys. Condens. Matter
17
, 6307
(2005
).27.
S.
Cook.
H.
Ohkita
, Y.
Kim
, J. J.
Benson-Smith
, D. D. C.
Bradley
, and J. R.
Durrant
, Chem. Phys. Lett.
445
, 276
(2007
).© 2013 AIP Publishing LLC.
2013
AIP Publishing LLC
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